Cellular wireless is an increasingly popular means of personal communication in the modem world. People are using cellular wireless networks for the exchange of voice and data with cellular telephones, Personal Digital Assistants (PDAs), cellular telephone modems, and other devices. In principle, a user can seek information over the Internet or call anyone over a Public Switched Telephone Network (PSTN) from any place inside the coverage area of the cellular wireless network.
An important feature of cellular wireless networks is an ability to locate the geographical position of a mobile station. Such a feature was developed initially to assist emergency services in locating a mobile station. For example, in the United States, the Federal Communications Commission (FCC) has mandated the implementation of “Enhanced 911” (E911) services.
The E911 mandate was divided into two phases. According to Phase 1, the location must be identified with an accuracy of at least cell and sector. As this information is typically maintained by a wireless cellular carrier in a subscriber's home location register (HLR), Phase 1 presents little technical challenge. According to Phase 2, the location must be provided with an accuracy of at least 100 meters (or 50 meters for handset-originated methods such as global position satellite (GPS)), which is far more granular than the cell and sector information maintained in the HLR. In response, the Telecommunications Industry Association (TIA) proposed a standard for “Enhanced Wireless 9-1-1, Phase 2,” entitled “Wireless Enhanced Emergency Services” or “TL1/EIA/IS-J-STD-036–A” (J-STD-036-A), the entirety of which is hereby incorporated by reference.
In order to achieve the accuracy specified by Phase 2, a cellular wireless network may employ a special position determining entity (PDE) and location determining techniques. Alternatively, a mobile station itself may employ a position determining system such as a GPS system and may relay its position to the network, for reference by the emergency services. The emergency services may then use the position of the mobile station to help assist a user of the mobile station.
Another important feature of cellular wireless networks is an ability to initiate and participate in a real-time media conference with one or more designated target users at other mobile stations. A conference server such as a multipoint control unit (MCU), conference bridge, switch or other entity can reside in the communication network and can function as a bridging or switching device between the participating stations, to support the conference session. The conference server may provide an “instant connect” service, where a user of one mobile station can readily initiate the real-time media conference with other mobile stations.